1 Field of the Invention
The present invention relates to a device for producing thermoplastic resin continuous length sections, or a thermoplastic resin structure reinforced with unidirectional aligned long fibers by impregnating continuous reinforcing fiber bundles with a molten thermoplastic resin. More specifically, the present invention pertains to a device for producing thermoplastic resin continuous length sections, which is characterized by the use of a shaping nozzle having a specific shape and which permits not only the inhibition of pill-formation due to fiber breakage, but also highly stable production of the sections.
2 Description of the Prior Art
There have already been proposed a variety of methods (or devices) for satisfactorily impregnating reinforcing fiber bundles with a molten resin, such as those disclosed in, for instance Japanese Examined Patent Publication No. Sho 63-37694. These methods permit the production of thermoplastic resin continuous length sections excellent in the impregnation ability. However, the inventors of this invention have exhaustively investigated these methods and have thus found that they should be improved on the point specified below:
Fibers undergo fiber breakage as the device is operated over a long period of time and this accordingly results in the pill-formation. Moreover, pills thus formed plug the shaping nozzle of the device, this nozzle plugging would lead to further fiber breakage and the continuous length sections are ultimately broken. Thus, the operation of the device must be interrupted.
Accordingly, it is an object of the present invention to provide a device for producing thermoplastic resin continuous length sections reinforced with long fibers, which can eliminate the foregoing various problems associated with the conventional techniques and which can provide a means for preventing the formation of any pill frequently observed in shaping nozzles positioned at the downstream end of an opening-impregnation device even after the operation thereof over a long period of time.
Another object of the present invention is to provide a device for producing thermoplastic resin continuous length sections reinforced with long fibers, which can thus permit stable production of such continuous length sections over a long period of time.
The inventors of this invention have conducted various studies to solve the foregoing problems associated with the conventional techniques, have found that the use of a shaping nozzle having a specific configuration is quite effective for the solution of the problems and thus have completed the present invention.
According to the present invention, desired effects of the invention can be accomplished by embodiments each comprising any combination of the following characteristic properties:
1) A pultrusion device for producing thermoplastic resin continuous length sections reinforced with long fibers, wherein the vertical angle (xcex1) of an upstream conical surface, which constitutes a shaping nozzle perforated through the downstream end wall of the device ranges from 15 to 35 degrees and the shaping nozzle has a land portion having a length of 1 to 5 mm in the downstream area subsequent to the upstream conical surface.
2) The production device as set forth in the foregoing item 1), wherein the vertical angle (xcex1) of the upstream conical surface constituting the shaping nozzle ranges from 20 to 30 degrees.
3) The production device as set forth in the foregoing item 1) or 2), wherein the shaping nozzle has a thickness, on the central axis extending from the upstream end to the downstream end of the downstream end wall of the pultrusion device, ranging from 5 to 35 mm.
4) The production device as set forth in any one of the foregoing item 1) to 3), wherein the shaping nozzle has a thickness, on the central axis extending from the upstream end to the downstream end of the downstream end wall of the pultrusion device, ranging from 15 to 30 mm.